Gasoline, diesel fuel or antiknock fluids containing an exhaust emission reducing additive

ABSTRACT

Mono- and di-alkanoates, aralkanoates and benzoates of benzylidene bisphenols reduce combustion chamber deposit formation and exhaust hydrocarbon emission increase of internal combustion engines.

United States Patent inventor App]. No.

Henry G. Braxton, Jr.

Franklin Village, Mich.

Mar. 13, 1970 Nov. 23, 1971 Ethyl Corporation New York, N.Y.

Original application Feb. 27, 1967, Ser. No. 619,003, now Patent No. 3,547,958. Divided and this application Mar. 13, 1970, Ser. No. 19,465

GASOLINE, DIESEL FUEL OR ANTIKNOCK FLUIDS CONTAINING AN EXHAUST EMISSION REDUCING ADDITIVE 16 Claims, No Drawings [51] Int. Cl. C09k 3/00, C101 1/18 [50] Field 01 Search 44/66, 70, 78; 252/57, 386; 260/395 [56] Reierences Cited UNITED STATES PATENTS 3,484,217 12/1969 O'Neill 44/78 X 3,484,218 12/1969 Braxton et a1. 44/78 X Primary Examiner-Daniel E. Wyman Assistant Examiner-W. .1. Shine Attorney-Dona1d L. Johnson ABSTRACT: Monoand di-uikanoates, aralkunoates and benzoatcs of benzyiidene bisphenois reduce combustion chamber deposit formation and exhaust hydrocarbon emission increase ofinternal combustion engines.

GASOLINE, DIESEL FUEL OR ANTIKNOCK FLUIDS CONTAINING AN EXHAUST EMISSION REDUCING ADDITIVE Cross-Reference to Related Application This application is a Division of application Ser. No. 619,003, filed Feb. 27, 1967 now Pat. No. 3,547,958.

BACKGROUND OF THE INVENTION Hydrocarbons are reported to react with ozone in the atmosphere, forming irritants. When the level of these irritants becomes high enough, there results what is commonly referred to as photochemical smog. Thus, a need exists for a method to reduce the amount of hydrocarbons introduced into the atmosphere from various sources. One source is exhaust gas of internal combustion engines. Previous means of reducing exhaust emissions have concentrated on the secondary oxidation of unburned exhaust products employing either catalytic oxidizing methods or direct flame oxidation in the exhaust system. If the amount of unburned hydrocarbons initially in the exhaust can be reduced, the need for secondary oxidation is diminished. Most previous attempts to reduce the initial hydrocarbon content of the exhaust gas have concentrated on mechanical means such as improved carburetion. The present invention provides a method of reducing exhaust emission and engine deposits through the use of an exhaust emission reducing additive.

SUMMARY OF THE DISCLOSURE This invention relates to a method of reducing the combustion chamber deposit formation and the increase in the level of exhaust hydrocarbon emission normally observed during the life of an internal combustion engine. A new internal combustion engine having an acceptable exhaust hydrocarbon level often exhibits an increase in this initial level during use, giving rise to an unacceptable emission level. The present invention provides a simple method of decreasing this increase in emission level by as much as 60 percent. This can be accomplished by merely adding a small amount of an emission control additive to the fuel or lubricant used in the engine or otherwise providing means for getting the additive into the combustion zone.

An object of this invention is to provide a means of reducing the deposits formed in an internal combustion engine. A further object is to reduce the increase in exhaust hydrocarbon emission normally observed during the life of an internal combustion engine.

These and other objects are accomplished by providing an exhaust emission reducing compound having the formula:

wherein R and R are independently selected from the group consisting of alkyl radicals containing from one to about 20 carbon atoms, aralkyl radicals containing from seven to about 20 carbon atoms, aryl radicals containing from six to about 20 carbon atoms and cycloalkyl radicals containing from five to about 20 carbon atoms; R R.,,R and R are independently selected from the group consisting of hydrogen, alkyl radicals containing from one to about 20 carbon atoms, aralkyl radicals containing from seven to about 20 carbon atoms, aryl radicals containing from six to about 20 carbon atoms and cycloalkyl radicals containing from five to about 20 carbon atoms, R, is selected from the group consisting of hydrogen, alkyl radicals containing from one to about 20 carbon atoms, aralkyl radicals containing from seven to about 20 carbon atoms, cycloalkyl radicals containing from tive to about 20 carbon atoms, and aryl radicals containing from six to about 20 carbon atoms, and Z is selected from the group consisting of hydrogen and radicals having the formula:

wherein R-, is selected from the same group previously 10 described for this radical.

Some examples of these compounds are: 4.4'-ben.zylidenebis( 6-tert-butyl-o-cres0l )diacetate 2,2-benzylidenebis(4,6-dimethylphenol)dibutyrate 2,2'-(p-sec-eicosyl-benzylidene)bis(4-sec-eicosyl-6- methylphenol)distearate 2,6-di-tert-butyl-6'-methyl-4,2-benzylidenediphenol formate 4,4-(3,5-di-tert-butyl-benzylidene)bis(osecamylphenol )dioleate 4,4'-(p-sec-nonyl-benzylidene)bis(2,6-

dimethylphenol )dibenzoate 5,6-dimethyl-2-sec-butyl-2-isopropyl-4,4'-benzylidene diphenol l -acetate- 1 -laurate 2,6-dimethyl-2'-phenyl-4,4'-benzylidenediphenol 2 5 tyrate 4,4-(p-methyl-benzylidene)bis[Z-(a-methylbenzyl-S- methylphenolldistearate 4,4'-benzylidenebis( 2,6-dicyclohexylphenol )dibutyrate 2,5-di-tert-butyl-2-(a -methylbenzyl)-5'-methyl- 4,4'-(3- 3 imethyl-S-phenylbenzylidene)diphenol diacetate 2,4'-benzylidenebis(o-tert-octylphenol)diacetate In a preferred embodiment of this invention, R and R, in formula I are bonded to the carbon atom of their respective benzene nuclei at the position ortho with respect to the carbon :atom in said benzene nuclei bonded to oxygen and are lselected from the group consisting of alkyl radicals containing from one to 20 carbon atoms, aralkyl radicals containing from @seven to 20 carbon atoms and cycloalkyl radicals containing ffrom five to 20 carbon atoms. These compounds have the fol- 4() Ilowing formula, in which R,, R R R R, and Z are selected ,from the same groups defined for formula I and R, and R are ,selg ted from the above described group.

l-bu- 'Some examples of these preferred embodiments are:

2,6-di(a-methylbenzyl)-2',6'-dimethyl-4,4-benzylidene diphenol l'-acetate 2,6-diethyl-2',6-di-n-propyl-4,4-(p-nonylbenzylidene)diphenol l-acetate l'-butyrate 2,6-di-tert-butyl-2"-dimethyl-4,4'-benzylidenediphenol diacetate 2,2,6-trimethyl-6-tert-octyl-4,4'-benzylidenediphenol diphenol diolcate In a more preferred embodiment the additives have formula II and R and R, are selected from the group consisting of alpha-branched alkyl radicals containing three to 20 carbon atoms, alpha-branched aralkyl radicals containing eight to 20 carbon atoms and cycloalkyl radicals containing six to 20 carbon atoms; R and R are selected from the group consisting of alkyl radicals containing one to 20 carbon atoms, cycloalkyl radicals containing six to 20 carbon atoms and aralkyl radicals containing seven to 20 carbon atoms; R, and R,, are hydrogen; Z is a radical having the formula:

and R, is an alkyl radical containing from one to about 20 carbon atoms. Examples of this embodiment are:

4,4'-be nzylidenebis( 6-tert-butyl-o-cresol )diacetate 4,4-benzylidenebis(2,6-di-sec-butylphenol)dibutyrate 4,4'-benzylidenebis(2,6-di-tert-butylphenol)dibutyrate 4,4'-benzylidenebis(2,6-di-tert-butylphenol)diacetate 4,4'-benzylidenebis(2,6-di-tert-butylphenol)dihexoate 4,4'-benzylidenebis(2,6-di-tert-butylphenol)distearate 2,6di-tert-butyl-2"-diisopropyl-4,4'-benzylidenediphenol dihexoate 4,4-benzylidenebis[ o-(a-methylbenzyl )-o-cresol ldilaurate 4,4'-benzylidenebis(2.6-di-sec-eicosylphenol)dioleate 4,4-benzylidenebis(6-tert-octyl-o-cresol)distearate Thus, it can be seen from the examples that a preferred group of alkyl radicals within the definition of R is selected from the group consisting of methyl, propyl, pentyl, undecyl, heptadecyl, and 9-heptadecenyl radicals.

The most preferred additive is 4.4-benzylidenebis(2,6-ditert-butylphenol)diacetate.

The additives are readily made by acylation of a benzylidenebisphenol. The benzylidenebisphenols are readily prepared by the reaction of the appropriate phenol with a benzaldehyde in a solvent using an acid or base catalyst. A suitable process is described by Filbey et al. in U.S. Pat. No.

2,807,653. The following example will serve to illustrate a method of making the emission control additives of this invention. All parts are parts by weight unless otherwise stated.

EXAMPLE 1 Preparation of 4,4'-Benzylidenebis- (2,6-di-tertbutylphenol) In a reaction vessel equipped with stirrer, condenser, thermometer and reagent introducing means was placed 6.6 parts of potassium hydroxide dissolved in 400 parts of isopropanol. To this solution under a nitrogen atmosphere was added 206 parts of 2,6-di-tert-butylphenol and 53 parts of benzaldehyde. Towards the end of the addition solids began to appear in the reaction vessel. After stirring for 2 hours at 40 C., the solids were filtered off to give a good yield of 4,4'-benzylidenebis(2,6-di-tert-butylphenol).

Conversion to the Diacetate To a reaction vessel equipped with stirrer, thermometer and cooling means was added 340 parts of ethyl acetate. 21.6 parts of acetate anhydride and 6 parts of 76 percent perchloric acid. The mixture was allowed to stand 30 minutes at room temperature and then, while stirring, it was cooled to C. An additional 1 10 parts of acetic anhydride was added and the mixture stirred at 0-5 C. for one hour.

In a second reaction vessel was placed 167 parts of 4,4- benzylidenebis(2,-di-tert-butylphenol) and the above acylating solution was added to it over a 30 minute period. At first, the solids dissolved, but after stirring an hour, a precipitate formed. Then 200 parts of water were added followed by 900 parts of a 75 percent aqueous pyridine solution. After stirring 30 minutes the mixture was neutralized with 50 percent sodiurn hydroxide to a pH of about 8. The mixture was further diluted with 7000 parts of water and the solid product removed by filtration. The yield was l90 parts, melting at l79-l82 C. After recrystallization from ethanol the melting point was l80-l 82 C. Infrared confirmed the identity of the compound as 4,4-benzylidenebis(2,6-di-tert-butylphenol)diacetate.

The above procedures are generally applicable to the preparation of a wide variety of benzylidenebisphenol acylates. Further discussion of a suitable method of acylating phenolic hydroxyl radicals is published inkAnalytical Chemistry," 32, 987 (1960). Other methods of acylating hydroxy groups using the appropriate acid, acid anhydride or acid chloride are well-known in the art and these can be advantageously used to prepare the acylated derivatives of benzylidenebisphenols.

The acylation process may be carried out on a mixture of benzylidenebisphenols resulting in a mixture containing a substantial amount of benzylidenebisphenol acylates. The preferred method of making these mixtures is to merely alky-| late the phenol using well-known methods, forming mixtures of mono-, diand tri-substituted phenols. Preferably, the mixtures are predominantly disubstituted phenol. These mixtures are then reacted with benzaldehyde in the presence of an acid or base catalyst, forming a mixture containing a substantial amount of benzylidenebisphenols. Following this, the mixture is acylated so that a substantial amount of the phenolic hydroxyl radicals are acylated resulting in a reaction product containing a substantial amount of benzylidenebis(hydrocarbylphenol)acylate. The following example will serve to illustrate this embodiment of the invention.

EXAMPLE 2 In a reaction vessel is placed 940 parts of phenol and 20 parts of phosphoric acid. The mixture is warmed to C., while stirring, and 1 l2 parts of isobutylene is added beneath the liquid surface over a period of one hour. Following this, the reaction mass is washed, yielding a mixture containing predominantly dibutylated phenols together with some monoand tri-butylated phenol. To the mixture of phenols is added 2000 parts of isopropanol and 25 parts of potassium hydroxide. The mixture is heated to reflux and 550 parts of benzaldehyde is added over a one hour period. The reaction mixture is stirred at reflux one hour and then cooled to room temperature, and I000 parts of water is added, causing the benzylidenebis(butylated phenol) mixture to precipitate. The aqueous phase is removed and the residue heated to [00 C. at 20 mm. Hg to remove residual water. Then, 2000 parts of trichloroethylene and l00 parts of anhydrous zinc chloride is added. Following this, i300 parts of n-butyrylchloride are added over a 30 minute period at 50-60 C. The temperature is raised to reflux and, after one hour, the mixture is cooled to 'room temperature and washed with water. The trichloroethylene is distilled off leaving a resinous product 'which contains a substantial amount of benzylidenebis(butylated phenol) monoand di-n-butyrate within the scope of this invention.

EXAMPLE 3 Alkylation of phenol with isobutylene is carried out following the procedure of Ecke et al., U.S. Pat. No. 2,83 l .898. The

reaction product consists essentially of percent 2,6di-tertbutylphenol, 15 percent o-tert-butylphenol, 7 percent 2,4,6-

tri-tert-butylphenol, and 3 percent other isomers. To another reaction vessel equipped with stirrer, thermometer and heating means is placed 2000 parts of isopropanol, 18 parts of benzaldehyde remaining in the product are distilled out by heating the product to 100 C. and reducing the pressure to 20 mm. Hg. The resulting product is a mixture consisting substan-' tially of benzylidenebis(monoand di-butylphenol). This mixture is acetylated employing the general procedure of example I. The benzylidenebis(butylated phenol) mixture is placed in a reaction vessel fitted with a stirrer and thermometer. A solution of 5100 parts of ethylacetate, 1980 parts of acetic anhydride and parts of 76 percent perchloric acid is added to it while stirring at 20-30 C., over a period of 4 hours. Stirring is continued an additional hour, during which time the temperature is raised to 50 C. It is stirred at 50 C. for an hour and then cooled to room temperature. It is diluted with 3000 parts of water and neutralized to a pH of about 8 with sodium hydroxide. The aqueous layer is removed and the remaining product water washed until the ethylacetate has been substantially removed. The resultant product is a mixture of acetylated benzylidenephenol products containing a substantial amount of benzylidenebis(mono-and di-tert-butylphenol)diacetates, previously described as within the scope of the present invention.

The additives of this invention can be used to reduce emissions and combustion chamber deposits resulting from the use of a broad range of liquid hydrocarbon fuels including both spark ignition and diesei fuels. It is especially useful in gasoline used in spark ignition engines. These liquid hydrocarbon fuels have a boiling range of from about 95 to about 400 F. and contain aliphatic, aromatic, olefinic and naphthenie hydrocarbons. The hydrocarbon fuels may contain other materials frequently used in such fuels. For example, the fuels may contain antiknock agents such as tetraethyllead, tetramethyllead, triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, trivinylethyllead, ferrocene, methyl ferrocene, iron carbonyl, methylcyclopentadienyl manganese tricarbonyl, methylcyclopentadienyl nickel nitrosyl, N,N-dimethylaniline, and the like. When metallic antiknock agents are employed, the fuels generally contain a scavenging agent. A particularly useful scavenging agent when lead alkyls are employed are the halohydrocarbons such as ethylenedichloride, ethylenedibromide, and the like. An especially useful fuel in this invention is a fuel containing from 0.5 to 6 grams of lead per gallon as tetraalkyllead and from 1.5 to 2.5 gram atoms of chlorine as a chlorohydrocarbon per gram atom of lead and from 0.5 to 1.5 gram atoms of bromine as a bromohydrocarbon per gram atom of lead. Preferred tetraalkyllead antiknocks are tetraethyl lead and tetramethyl lead. The most preferred chlorohydrocarbon is ethylenedichloride, and the most preferred bromohydrocarbon is ethylenedibromide.

It is often desirable to include an induction aid in the gasoline compositions containing the benzylidene bisphenol acylates. This is because some of the additives are high? molecular weight, and, with a normal vaporization type carburetor, induct into the combustion chamber with difficulty. Thus problem is not encountered in diesel engines or fuel injected spark ignited engines. Suitable induction aids are solvents boiling in the range of from about 300-500 F. such as kerosene, alkylated aromatics, for example, isopropyl benzene, diethyl benzene, and the like; ketones boiling fromj 300-500 F. such as cyelohexanone, ethylcyclohexanone, ethyl-n-butyl ketone, diisobutyl ketone, and the like; ethers boiling in the 300-500 F. range such as diethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, and the like;. ether alcohols such as ethylene glycol monoisobutyl ether, ethylene glycol mono-n-butyl ether; esters such as isoamyl. propionate, cyclohexyl acetate, furfuryl acetate, and the like. Of the foregoing examples, the preferred induction aids arekerosenes boiling from 300 to 500 F.

The amount of induction aid employed varies from none to about 5 percent depending upon the ease of inductibility and the carburetor design. When an aid is used, a preferred concentration is from O.l to 5 percent. A more preferred range is from about 0.2 to l percent.

The fuels can also contain deposit modifying agents such as phosphorus-containing additives, for example, tricresylphosphate, cresyldiphenylpyosphate, trimethylphosphate, dimethylcresylphosphate, tris(flchloropropyl)phosphate, and the like.

The fuels frequently contain antioxidant additives such as 2,6-di-tert-butylphenol; 2,o-di-tert-butyl-4-methylphenol, 4,4'-methylenebis(2,o-di-tert-butylphenol); 2,2- methylenebis(4-methyl-6-tert-butylphenol); phenylenediamines; p-nonylphenol; mixed alkylated phenols, 4,4- thiobis(3-methyl-6-tert-butylphenol), and the like.

Other materials can be present in the fuel such as de-icers,. metal deactivators, pour point depressants, boron esters,. nickel alkyl phosphates and dyes.

The following examples illustrate the preparation of typical improved fuel compositions of this invention.

EXAMPLE 4 Boiling runge l0l-375 F. Research Octane Number 93 Aromatics (volume 38 i Olefinics (volume l0 Aliphutics (volume 12) To this gasoline is added a tetraethyllead antiknock agent containing two gram atoms of chlorine as ethylenedichloride per gram atom of lead and one gram atom of bromine as ethylenedibromide per gram atom of lead. The quality of tetraethyllead antiknock agent added is sufficient to provide 3. 17 grams of lead per gallon of fuel. There is then added sufficient 4,4'-benzylidene bis(2,6-di-tert-butylphenol)diacetate to give a concentration of 0.25 weight percent. There is then ,added 0.25 weight percent of cyclohexanone as an induction aid. The mixture is agitated until thoroughly mixed, resulting .in a gasoline having reduced exhaust emission properties.

EXAMPLE 5 To a blending vessel is added 1000 gallons of a reformate gasoline having the following properties:

Boiling range 94-403 F. Research Octane Number 97 Aromatics (volume '11) 62 Olclinics (volume 5 Aliphntics (volume 3 3 To this gasoline is added a tetramethyllead antiknock mixture containing one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide. A quantity suffi-- Ecient to provide 2.12 grams of lead per gallon is added. There is also added, as an antioxidant, a mixture of butylated phenols containing about 75 percent 2,6-di-tert-butylphenol, such that the gasoline contains 0.1 weight percent of the antioxidant mixture. Then 0.05 weight percent of 4,4'(p-nonylbenzylidene)bis(2,6-di-tert-butylphenol) dioleate together with 1 percent of diethylene glycol diethyl ether is added and the mixture thoroughly stirred, resulting in a gasoline giving reduced emission and combustion chamber deposits weight .when used to operate a spark ignition internal combustion engme.

Good results are also obtained in the above example when other benzylidene bisphenol acylates such as those previously listed are employed as the emission and deposit-reducing agent.

EXAMPLE 6 To a blending vessel is added 1000 gallons of a gasoline having the following properties:

Bolling range l03399 F. Research Octane Number Aromatics (volume Aliphutics (volume Olefins (volume '1) To this gasoline is added an antiknock fluid as shown in example 9 in quantities sufficient to give a lead concentration of 3.0 grams per gallon as tetraethyl lead. This addition concurrently adds b 4,4'-benzylidene bis(2,6-di-tert-butylphenol)diacetate in an amount equal to 0.05 weight percent.

EXAMPLE 7 To a blending vessel is added 1000 gallons of gasoline having the following properties:

Boiling rung: Research Octune Motor Octune Aromatics (volume 27 Aliphntics (volume 96) 66 Olefins (volume 7 Sulfur 0.05%

To this gasoline is added 0.25 weight percent of a kerosene. having a boiling range of 356-450 F., visc. at 100 SUS of 73, flash point of 320 F., pour point 30 F., specific gravity 0.893, Conralson carbon of 0.02 weight per cent and Kauributanol No. of 28. There is then added 2.6 grams of lead per properties.

EXAMPLE 8 To a blending vessel is added 1000 gallons of a diesel fuel having a boiling range of from 430-572 F., and a cetane number of 47. To this is added 0.3 weight percent amyl nitrate as a cetane improver. There is then added 0.2 weight percent of 4,4'-benzylidene bisl(2,6di(a-methylbenzyl)phenol]dip ropionate, resulting in a diesel fuel having reduced exhaust emission and deposit forming properties.

In any of the previous examples, the forementioned emission-reducing compounds can be employed, giving fuels having reduced emission properties. Also, the concentrations may be varied from those shown. In general, a concentration of from about 0.01 to 3 weight percent of the emission-reducing additive can be employed. A preferred concentration range is from about 0.05 to about 1 weight percent, and a most useful range is from about 0.1 to 0.5 weight percent.

An especially useful means of adding the benzylidene bisphenol acylates to gasoline is to include them in the antiknock fluid concentrate which is normally added to gasoline so that the entire operation can be accomplished in a single blending step. These antiknock fluids contain an antiknock, such as, but not limited to, tetraalkyl lead plus other materials, which beneficially effect the use of the antiknock. Especially useful tetraalkyl lead antiknocks are tetraethyl lead, tetramethyl lead. mixtures thereof, alkyl leads containing both ethyl and methyl groups, and mixtures thereof. These antiknock fluids usually contain a halogen compound as a scavenger. The most frequently employed halogen scavengers are ethylene dichloride and ethylene dibromide. The quantities of these scavengers can be varied within a wide range, but the best results are obtained when the antiknock fluid contains from 0.5 to 2 theories of chlorine as ethylene dichloride and from O to 1.0 theories of bromine as tehylene dibromide. A theory" is equal to 2 gram equivalents of halogen per gram mole of lead. in other words, one theory of halogen is sufficient to convert the lead in a tetraalkyl lead to lead dihalide.

An amount of benzylidene bisphenol acylate is added to the antiknock fluid such that when the antiknock fluid is added to gasoline in an amount sufficient to raise the octane number of the gasoline to the desired value there will also be included in the gasoline an emission and deposit reducing amount of benzylidene bisphenol acylate. A preferred range of benzylidene bisphenol acylate concentration in the gasoline is from. about 0.05 to 3 weight percent. Hence, a useful range of benzylidene bisphenol acylate in tetraalkyl lead antiknock fluids is from about 0.45 to 27.2 parts of the benzylidene bisphenol per part of lead as tetraalkyl lead. This amount will supply from 0.05 to 3 weight percent of the benzylidene bisphenol acylate when sufficient antiknock fluid is added to the gasoline to supply 3 grams of lead per gallon as tetraalkyl lead. When more or less lead is desired, the concentration range of benzylidene bisphenol acylate in the fluid can be varied accordingly to furnish the desired benzylidene bisphenol acylate concentration. Following are some representative examples of antiknock fluids containing exhaust and deposit reducing benzylidene bisphenol acylates.

EXAMPLE 9 An antiknock fluid is prepared by blending the following ingredients:

tetrnethylleud 1,000 purts ethylene dihromide 290 parts ethylene dichloride 306 parts 4,4'-henzylidenc hls(2.6- di-tert-hutylphenol) diucetute 290 parts kerosene putts orunge dye 5 parts EXAMPLE 10 An antiknock fluid is prepared by blending the following ingredients:

, tetrumethylleud 1,000 parts ethylene dihromide 295 parts trimethyl phosphate 155 parts 4 4'-(p-nonyl benzylidene) bis( 2,6-di-sec-dodecylphenoU-di-butyrute 17.400 putts kerosene 200 parts The above examples are merely illustrative of the typical an- .tiknock fluids which can be prepared. Similar antiknock fluids can be prepared by employing other antiknock agents such as -triethylmethyllead, diethyldimethyllead, trimethylethyllead, tetravinyllead, triethylvinyllead, diethyldivinyllead, *trivinylethyllead, ferrocene, methylferrocene, iron carbonyl, .methylcyclopentadienyl manganese tricarbonyl, methylfcyclopentadienyl nickel nitrosyl, N,N-dimethylaniline, and mixtures of any of the foregoing. Likewise, any of the previ- 'ously described benzylidene bisphenol acylates can be employed in these antiknock fluids in quantities that will give the 'desired concentration in the final gasoline blend. These concentrations are easily determined by those experienced in blending additives in gasoline.

Tests have been conducted to demonstrate the useful exhaust emission properties of the present compounds. in these .tests, a single cylinder overhead value engine, having a 10:1 compression ratio and a 36 cubic inch displacement, was operated on a typical commercial gasoline containing 3.17 grams of lead as a commercial tetraethyllead antiknock mixture containing one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide. The engine was idled for 45 seconds and then run at 50 percent wide open throttle for seconds under the following conditions.

Air/fuel ratio l3 r.p.m. 1,370 Ignition timing l5 BTC The above cycle was continuously repeated until both deposits and hydrocarbon emissions had stabilized. This usually required from about 100-145 hours of operation. The hydrocarbon content of the exhaust gas was determined using a Beckman l09-A Flame lsomerization Detector, and the deposits were determined by disassembling the engine, removing andweighing the deposits. The procedure was first carried out using a fuel without the emission reducing additive to obtain a base line exhaust emission increase and then repeated on the same fuel containing an emission reducing additive. This carbon atoms. was followed by another test on the fuel, again without the 3. The composition of claim 1 wherein said composition is emission additive, to reconfirm the baseline. Using this gasoline. procedure. h ll i lt I lei-ms f the er ent d 4. The composition of claim 3 containing an octane-increastion in exhaust hydrocarbon emlsslon increase and total coming am g l n llic a n k g ntb fl chamber deposits were b i d using i i reducn 5. The composition of claim 4 wherein said antiknock agent ing additives of this invention. is a tetraalky 6. The composition of claim 5 wherein said tetraalkyllead is Reduction 0F tetraethyllead. "gg m 7. The composition of claim 6 containing from 0.5 to 6 increase, we m grams of lead per gallon as tetraethyllead. Addltiv P timei 8. The composition of claim 7 wherein said compound is 4,4-bonz lideno bis(2,(S-di-tort-butyl further defined in that R,, R R and R are tert-butyl radicals Phmml (B-Comte 62 73 and R and R, are bonded to the carbon atom of their respecl tive benzene nuclei at the position ortho with respect to the As these results show, the emissionreducing additives of the; carbon atom in said benzene nuclei bonded to oxygen; and R present invention effectively reduce both exhaust emission in-? and R are hydrogen and Z is the radical: crease and engine deposits.

I claim: 0 i. A composition selected from the group consisting of, "li n, gasoline and diesel fuels and tctrnnlkyllcutl untlknock fluids f m i i u b mi h b d i d h p, gmig-i Itliiti R isu hydrocurbyl ulkyl radical containing from one to 20 sion reducing amount ofu compound having the formula: l M

' 9. The composition of claim 8 wherein said compound is 0 g4,4-benzylidene bis(2,6-di-tert-butylphenol)diacetate. 0 2 IL 1 10. The composition of claim 3 wherein said compound is further defined in that R and R are independently selected R1 R: from the group consisting of a-branched hydrocarbyl alkyl :radicals containing from three to about 20 carbon atoms, a-

| branched aralkyl radicals containing from about eight to about 20 carbon atoms, and cycloalkyl radicals containing R3 yfrom about six to about 20 carbon atoms, R and R, are

{selected from the group consisting of hydrocarbyl alkyl radia Ra icals containing from one to about 20 carbon atoms, cycloalkyl radicals containing from six to about 20 carbon atoms, and wherein R, and R are independently selected from the group aralkyl radicals containing from seven to about 20 carbon consisting of hydrocarbyl alkyl radicals containing from one to i ms, R5 and R6 ar hydrogen, Z is a radical having the forabout 20 carbon atoms, aralkyl radicals containing from seven to about 20 carbon atoms, mononuclear aryl radicals contain- 0 ing from six to about 20 carbon atoms and cycloalkyl radicals A containing from five to about 20 carbon atoms; R R,,, R and 1 R are independently selected from the group consisting of hydrogen, hydrocarbyl alkyl radicals containing from one to about 20 carbon atoms, aralkyl radicals containing from seven to about 20 carbon atoms, mononuclear aryl radicals contain ing from six to about 20 carbon atoms, and cycloalkyl radicals containing from five to about 20 carbon atoms, R, is selected from the group consisting of hydrogen, hydrocarbyl alkyl radicals containing from one to about 20 carbon atoms, aralkyl of methyl PYOPYL Pemy" undecyl' heptadecyl, and radicals containing from seven to about 20 carbon atoms, tadecanyhad'cals' cycloalkyl radicals containing from five to about 20 carbon; The comPosition of claim 5 wherein said is atoms, and mononuclear aryl radicals containing from six to further defined m that R1 and R2 are ten'butyl radicals and R3 about 20 carbon atoms, and Z is selected from the group con-. and R4 are selemed from the group consisiing of hydrogen and sisting of hydrogen and radicals having the formula: ten'butyl radicals and R and R are hydrogen.

14. A composition of claim 13 wherein said compound 0 comprises a mixture consisting substantially of benzylidene ii bis-( butylated phenol) monoand di-n-butyrate.

15. A composition of claim 13 wherein said compound is wherein R is selected from the same group previously further defined in that Z is a radical having the formula: described.

2. The composition of claim 1 wherein said compound is 0 further defined in that R R R and R are tert-butyl radicals A and R and R are bonded to the carbon atom of their respec- 1 tive benzene nuclei at the position ortho with respect to the 5 carbon atom in said benzene nuclei bonded to oxygen; and R \Wherein 1 is a hydrocarbyl alkyl radical comaining from one and R,, are hydrogen and Z is the radical: about 20 Carbon ms- 16. A composition of claim 15 wherein said compound wherein R is selected from hydrocarbyl alkyl radicals conftaining from one to about 20 carbon atoms.

11. The composition of claim 10 containing an octane-in- 'creasing amount of a tetraalkyllead antiknock agent.

12. A composition of claim 11 wherein said compound is 0 t comprises a mixture consisting substantially of benzylidene g 7O bis-(monoand di-tert-butylphenol)diacetate.

and R is a hydrocarbyl alkyl radical containing from one to 20 =i= k ik 'further defined in that R, is selected from the group consisting 

2. The composition of claim 1 wherein said compound is further defined in that R1, R2, R3 and R4 are tert-butyl radicals and R3 and R4 are bonded to the carbon atom of their respective benzene nuclei at the position ortho with respect to the carbon atom in said benzene nuclei bonded to oxygen; and R5 and R6 are hydrogen and Z is the radical: and R7 is a hydrocarbyl alkyl radical containing from one to 20 carbon atoms.
 3. The composition of claim 1 wherein said composition is gasoline.
 4. The composition of claim 3 containing an octane-increasing amount of on organometallic antiknock agent.
 5. The composition of claim 4 wherein said antiknock agent is a tetraalkyllead.
 6. The composition of claim 5 wherein said tetraalkyllead is tetraethyllead.
 7. The composition of claim 6 containing from 0.5 to 6 grams of lead per gallon as tetraethyllead.
 8. The composition of claim 7 wherein said compound is further defined in that R1, R2, R3 and R4 are tert-butyl radicals and R3 and R4 are bonded to the carbon atom of their respective benzene nuclei at the position ortho with respect to the carbon atom in said benzene nuclei bonded to oxygen; and R5 and R6 are hydrogen and Z is the radical: and R7 is a hydrocarbyl alkyl radical containing from one to 20 carbon atoms.
 9. The composition of claim 8 wherein said compound is 4,4''-benzylidene bis(2,6-di-tert-butylphenol)diacetate.
 10. The composition of claim 3 wherein said compound is further defined in that R1 and R2 are independently selected from the group consisting of Alpha -bRanched hydrocarbyl alkyl radicals containing from three to about 20 carbon atoms, Alpha -branched aralkyl radicals containing from about eight to about 20 carbon atoms, and cycloalkyl radicals containing from about six to about 20 carbon atoms, R3 and R4 are selected from the group consisting of hydrocarbyl alkyl radicals containing from one to about 20 carbon atoms, cycloalkyl radicals containing from six to about 20 carbon atoms, and aralkyl radicals containing from seven to about 20 carbon atoms, R5 and R6 are hydrogen, Z is a radical having the formula: wherein R7 is selected from hydrocarbyl alkyl radicals containing from one to about 20 carbon atoms.
 11. The composition of claim 10 containing an octane-increasing amount of a tetraalkyllead antiknock agent.
 12. A composition of claim 11 wherein said compound is further defined in that R7 is selected from the group consisting of methyl, propyl, pentyl, undecyl, heptadecyl, and 9-heptadecanyl radicals.
 13. The composition of claim 5 wherein said compound is further defined in that R1 and R2 are tert-butyl radicals and R3 and R4 are selected from the group consisting of hydrogen and tert-butyl radicals and R5 and R6 are hydrogen.
 14. A composition of claim 13 wherein said compound comprises a mixture consisting substantially of benzylidene bis-(butylated phenol) mono- and di-n-butyrate.
 15. A composition of claim 13 wherein said compound is further defined in that Z is a radical having the formula: wherein R7 is a hydrocarbyl alkyl radical containing from one to about 20 carbon atoms.
 16. A composition of claim 15 wherein said compound comprises a mixture consisting substantially of benzylidene bis-(mono- and di-tert-butylphenol)diacetate. 